Method of amalgamating metals.



Patented July 22, I902.

P. A. KNAPPE. METHOD OF AMALGAMATING METALS.

uUUDHw HUD I II (Application filed Mar. '7, 1902.)

(No Model.)

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THE uonms PETERS 00., Puoiuunio. wasxmurou, 0.1:.

UNITED STATES PATENT OFFICE;

PAUL A. KNAPPE, OF GRANTVILLE, GEORGIA, ASSIGNOR, BY MESNE ASSIGN- MENTS, TO AMERICAN AMALGAMATING COMPANY, A CORPORATION OF GEORGIA.

SPECIFICATION forming part Of Letters Patent N0. 705,096, dated July 22, 1902. Application filed March 7, 1902. Serial N0.9'7,036. (No specimens.)

To all whom, it may concern:

Be it known that I, PAUL A. KNAPPE, a citizen of the United States, residing at Grantville, in the county of Ooweta and State of Georgia, haveinvented an Improvement in Methods of Amalgamating Metals, of which .the following description, in connection with the accompanyingdrawings,isaspecification,

like letters on the drawings representing like parts.

My invention relates to the amalgamation of metals by the use of free mercury. Amalgamation by free mercury when carried out successfully possesses many advantages over is other methods of extracting the precious metals; but in its practical application difficulties are encountered which have heretofore rendered the methods employed commercially inefiicient. One of the essential 2o requisites is that the pulp or mixture of comminuted ore and water should be so thoroughly intermingled with the mercury that the greatest possible portion of metal may have contact therewith to form the resultant amalgam. On the other hand, this intermingling must be carried out in such a manner as to prevent too violent an agitation of the mercury, since the latter is easily floured or finely dissipated, in which condition it is unfit for further amalgamation,

being carried off with the waste product, resulting in a loss of the mercury as well as of the more precious amalgam with which it may be associated. During this inter-mingling process, owing tothe difference in specific gravity, the bulk of the mercury tends to remain at the bottom of the receptacle in which the amalgamation is being carried on and the pulp tends to remain uppermost, there being a strong tendency to resist any force impelling the mercury upward or the pulp downward. It has heretofore been practically impossible to obtain a form of agitation that would cause proper mixture without flouring the mercury. The subsequent separation of the waste, commonly called gangue or sand, from the amalgam is ordinarily a process of settling dependent upon the difference in specific gravity between the two substances. The mixture during the separation must be undisturbed. to the extent of permitting the particles to rise or descend,

according to their relative specific gravity.

On the other hand, some disturbance of the mass must still be maintained to free the intermingled particles of mercury and amalgam from the gangue or sand and admit of their free circulation and ready response to the laws of gravitation; otherwise a large percentage of the amalgam will pass off with the gangue.

My invention aims to provide a method of amalgamation which shall'so combine the various essentials above mentioned as to produce better results than have heretofore been possible.

To enable my invention to be understood,

I will describe, referring to the accompanying drawings, one means of carrying out the same, it being understood, however, that my invention is not limited to the particular means disclosed.

Figure 1 is a side elevation of an amalgamator constructed to carry out my improved method Fig. 2 is a broken central longitudinal sectional view of the same, shown on a larger scale. Fig. 3 is a cross-sectional View taken on the line 3 3 in Fig. 2, and Fig. 4 is a similar sectional View on the line at 4:.-

In the drawings, A represents a cylindrical 8o tube having flanged ends by which it is coaXially bolted at one end to a similar tube B of greater diameter and at the other end to a head 0. At the opposite end of the tube 13 is a similar head 0, bolted through similar flanges. The heads 0 0 provide stuffingboxes D D, forming therewith bearings for the shaft E, which passes throughout the length of the two tubes andis provided at one end with a suitable. pulley F, through which proper rotary movement may be im parted to said shaft E. The amalgamatortubes formed as above described carry trunnions ti, resting in uprights S S. An inlet or feed pipe afor the introduction of pulp enters near the leading end of the tube A through an opening in a boss cast on. the upper side of said tube A. Directly beneath the entrance of said tube Otis placed a shield c, which may be of metal or other suitable material and is removably fitted in any convenient manner in the side of the tube A. A gangue or waste discharge pipe dhas communication with the tube B, preferably near the upper outer end thereof. At the under side of the tube B and preferably near its outer end is cast a boss, in which is screwed the plug g, containing a draw-off pipe 71. for the mercury, controlled by the valve As a convenient means for draining the amalgamator, but forming no essential feature thereof, I have shown a slight troughlike depression, formed, preferably, in the under wall of the tube B and diminishing in depth from the outer end of said tube toward the initial end, where the cross-section of the tube is substantially circular. This depression is so slight as to be scarcely perceptible in the View shown in Fig. 1, but will be more readily understood by inspection of Fig. 2 and the cross-section shown in Fig. 4.

A pipej for the discharge of water or other fluid into the amalgamator enters the same preferably at the point of juncture of the tube 13 with the tube A, being adapted to discharge its contents in a forwardly-inclined direction under the control of a valve 7t. It is to be understood, however, that I am not limited to the construction shown and that any suitable method of bringing the fluid into the amalgamator may be employed.

On the shaft E, within the tube A, except where they would conflict with the shield c, is placed a series of radial mixing-arms Z. As shown in the drawings, they appear in staggered sets of two, screwed into the shaft E or otherwise suitably attached thereto and adapted to be revolved within the tube A with but slight clearance. The shaft E carries another series of freeing-arms m, adapted to revolve within the tube B. These arms m are suitably dimensioned and disposed to produce a disturbance of the contents of the tube B without producing any substantial intermingling ofthe mercury and the gangue. Other means for mixing and freeing may be employed, and I am not limited to those above described, which are merely such as I have found well adapted in practice to carry out my method.

In Fig. 2 is diagrammatically shown a generator of electric current 0, which is omitted from Fig. 1 for the sake of clearness. This is electrically connected with the terminals 71 at, which have access to the interior of the tubes A B, respectively, through suitable insulating-plugs and are adapted to have contact with the meigcury therein contained to cause passage of the current through the mass of intermingled pulp and mercury in the mixing-chamber. The electric current is employed to increase and sustain the activity of the mercury and to prevent the latter from sickening. Any means for the passage of a current through the intermingled pulp and mercury may be used; but in practice I have found the employment of an interrupted or alternating current most eflective.

This amalgamator is employed to carry out my method in the following manner: The two chambers are filled to the desired level with mercury, which, for the sake of illustration, may be indicated by the dotted line in Fig. 2, but in practice is subject to variation. The pulp is fed through the inlet-pipe at to substantially fill the chamber of the tube A, but on entering the said chamber is. prevented from dropping on the mercury immediately below and fiouring the same by the protecting-shield c. The pulp is preferably fed to the amalgator, conducted therethrough, and finally removed therefrom through the agency of'pressure. As a convenient means for obtaining this pressure I have shown the pulpinlet pipe surmounted by a hopper, suitably elevated above the outlet-passage, so that the desired pressure may be obtained on feeding the pulp to the hopper. Any other means, however, for obtaining a suitable pressure may be employed. Under the influence of pressure the pulp is gradually worked from the initial end of the mixing-tube A to the settling or freeing'tube B. During its passage through the mixing-tube it is subjected to the steady action of the mixing-arms Z. This action is sufficiently mild to avoid the flouring of the mercury, and yet the available space within the mixing-chamber is so restricted that the particles of pulp are brought into contact with the mercury on slight movement,and the mixing-arms are so dimensioned and disposed that a thorough intermingling of the mercury and pulp is effected before the pulp reaches thesettling-chamber. The proportions of the settling-chamber and the size and disposition of the freeing-arms are such that the mixing action ceases here and the particles of sand and pulp, nowintermingled with bits of mercury and amalgam, are set intofreecirculation. This disturbanceofthe mixture and the resultant movement of the particles causes a freeing and separation of the heavier bits of mercury and amalgam, which pass downward, while the lighter particles of sand rise and are carried ofi through the outlet. Since the outlet-passage is located at the top of the chamber and the pulp passes therethrough under the influence of pressure, the settling-chamber is substantially filled with pulp above the line of mercury. It is to be understood, therefore, that the term restricted or confined space, as applied to the available space in the mixing-chamber, is used in a relative sense, and, further, that it is only used to distinguish a space in which the particles of sand cannot move freely without coming into mixing contact with the mercury from a space in which greater freedom of movement is allowed the sand particles for the separation therefrom of the mercury and the amalgam. It is also to be understood that this term has no reference ICC to the dimensions of such spaces, either actual or relative, for it is obvious that greater freedom in the movement of particles of pulp may be obtained in the settling-chamber by a mere change in the shape or proportions of said chamber as well as by an actual change in the dimensions of the same. My invention is not, therefore, limited to chambers of the particular shape, size, or proportions shown and described. The freeing action of the revolving arms employed in this larger chamber, as distinguished from the mixing action in the first chamber, is calculated to increase the circulation of the particles of sand and amalgam and aid the settling process; but as various means may be employed for accomplishing this purpose I am not limited to any particular kind of agitation. It is only necessary that this step should be carried out under such conditions as to aid the free circulation of the sand and the separation of the lighter from the heavier particles by gravitation. As the pulp passes through the settling-chamber it loses more and more of the entrained mercury, and by the time it reaches a position near the outlet-pipe it is free from substantially all of the mercury and amalgam and is ready to be carried off through the outlet-passage in the form of gangue. In addition to giving the particles of the mixture greater freedom of movement anda mild freeing action within this settling-chamber in distinction to a restricted movement and a mixing action in the amalgamating-chamber I have found it sometimes advantageous to intermingle with the gangue a quantity of Water or. other vehicle fluid, preferably as it passes from the amalgamating-chamber into the settling-chamber. This I accomplish in the above-described apparatus by admitting water through the pipe j. The addition of liquid at this point dilutes the pulp, aids the free circulation of the heavier particles, thereby materially improving the settling, and also acts as a vehicle to carry off the gangue through the outlet-passage. I do not, however, regard this as an essential step in my process.

It is to be observed that by placing the settling-chamber in open communication with the mixing-chamber I obtain an unimpeded circulation of the sand or pulp throughout the entire process and that there is nointerruption in its passage from the mixing to the settling chamber. The process, as above described, is a continuous one. The pulp fed into the hopper is brought into contact with a body of mercury and mingled therewith. Under pressure it. is carried through the mixing-chamber, and while still under the moving influence of pressure it is so acted upon as to permit a complete separation by settling and a removal of the gangue. The amalgamation is carried on without interruption until it is desired to withdraw the mercury and replace itwith a fresh charge. The withdrawal of the mercury is readily efiected through the pipe h.

It is to be understood that the structure described and shown, tho'ugh well adapted, as I have found, to carry out my method in practice, is submitted for illustrative purposes only, and that I am not limited to any particular structure or means for carrying it into effect.

1 claim- 1. The herein-described method for amalgamating metals, which consists in producing a pulp, bringing the same into contact with mercury, enforcing an intermingling of the mercury and the pulp, confining the mixed pulp and mercury within a restricted space during such intermingling, thereafter freeing the intermingled pulp and mercury from said restricted space, separating the heavier particles from the lighter by gravitation in a space less restricted for the circulation of the pulp particles, and preventing further intermingling.

2. The herein-described method for amalgamating metals, which consists in producing a pulp, filling a space with said pulp and with mercury in the presence of pressure, and enforcing an intermingling of the two,placing said filled space in communication with a second space, and permitting the latter to be filled with the intermingled pulp and mercury from the first, also in the presence of pressure, freeing the mixture in said second space from the mixture-enforcing action of the first space, settling the amalgam and mercury in said second space, and carrying off the lighter sand-and gangue under the pressure therein.

3. The herein-described method for amalgamating metals which consists in producing a pulp, bringing the same into contact with mercury, intermingling the mercury and pulp within a confined space, freeing the intermingled pulp and mercury from said confined space, opening up and freeing the materials thereof in a space less restricted for the circulation of the pulp particles, separating the heavier particles from the lighter by gravitation, and preventing further intermingling.

4. The herein-described method for amalgamating metals which consists in producing a pulp, bringing the same into contact with mercury, enforcing an intermingling of the mercury and the pulp, confining the mixed pulp and mercury within a restricted space during such intermingling, freeing the inter mingled pulp and mercury from said restricted space, diluting the same with liquid, separating the heavier particles from the lighter, and settling the same by gravitation,and preventing the reintermingling of the settled particles.

5. The herein-described method for amalgamating metals, which consists in producing a pulp, bringing the same into contact with mercury, intermingling the mercury and pulp within a confined space, freeing the vinter- &

mingled mass from said confined space, diluting the intermingled pulp and mercury, opening up the materials in the mass thus freed in a less restricted space, separating the heavier particles thereof by gravitation, and preventing the reintermingling of the settled particles.

6. The herein-described method for amalgamating metals, which consists in producing a pulp, introducing the same into a space containing mercury, said space being such that a slight movement of the pulp particles in certain directions results in contact with the mercury, causing such movement of the pulp as to enforce an intermingling of the same with the mercury, passing the mixed pulp and mercury into a space such that the pulp particles may move with. relative freedom without contact with mercury, opening up the material of the mixture by disturbing the same while in this space, permitting the separation of the heavier particles therefrom by gravitation, and preventing further intermingling.

7. The process of amalgamating metals,

which consists in forming a pulp, bringing the same into contact with mercury, enforcing an intermingling of the mercury and the pulp, confining the mixed pulp and mercury Within a restricted space during such intermingling, thereafter freeing the mixed pulp and mercury from said restricted space, separating the heavier particles by gravitation in a less restricted space, and causing the passage of an electric current through the intermingled pulp and mercury.

8. The herein-described method for amalgamating metals, which consists in producing a pulp, bringing the same into contact with mercury, agitating the pulp and mercury within a confined space to thoroughly intermingle the same, freeing the intermingled pulp and mercury from said confined space, subjecting the mass to a milder form of agitation in a less restricted space, separating the heavier particles from the lighter by gravitation, and preventing further intermin glin g of the same.

9. The herein-described method of amalgamating metals, which consists in producing a pulp, passing the same through a confined space containing mercury, intermingling the mercury and the pulp therein, passing the intermingled mercury and the pulp through a less restricted space, opening up the materials thereof, separating by gravitation the heavier particles from the moving mass, and

preventing the further intermingling of the same, said passage of the materials through the two spaces being continuous.

10. The herein-described method for amalgamating metals, which consists in producing a pulp, passing the same through a confined space containing mercury, enforcing an intermingling of the mercury and the pulp therein,

' passing the intermingled mercury and pulp through a less restricted space, separating roaooe therein the heavier particles from the lighter by gravitation, settling the same out of the path of the moving mass, and preventing further intermingling of the settled particles.

11. The herein-described method for amalgamating metals, which consists in passing pulp through a restricted space containing mercury, intermingling the two substances therein, passing the intermingled pulp and mercury to a less restricted space, diluting the same with liquid, separating the heavier particles from the lighter by gravitation, and settling said particles out of the line of flow of the moving mass.

12. The herein-described method for amalgamating metals, which consists in producing a pulp, bringing the same into contact with mercury, intermingling the mercury and pulp within a confined space, freeing the intermingled mass from said confined space, diluting the intermingled pulp and mercury with liquid, opening up the materials in the mass thus freed in a less restricted space, separating the heavier particles thereof by gravitation, and settling the same out of the line of flow of the moving mass.

13. The process of amalgamating metals, which consists in forming a pulp, bringing the same into contact with mercury, enforcing an intermingling of the mercury and the pulp, confining the mixed pulp and mercury within a restricted space (luring such intermingling, t-hereafter freeing the mixed pulp and mercury from said restricted space, separating the heavier particles by gravitation in a less restricted space, settling the same out of the line of flow of the moving mass, and causing the passage of an electric current through the intermingled pulp and mercury.

14. The herein-described method of amalgamating metals, which consists in producing a pulp, passing the same through a confined space containing mercury, intermingling the mercury and the pulp therein, causing the intermingled mass to travel in a substantially horizontal direction through a less restricted space, opening up the materials thereof during its passage through said less restricted space, and separating the heavier particles from the lighter by gravitation.

15. The herein-described method for amalgamating metals, which consists in producing a pulp, bringing the same into contact with mercury, enforcing an intermingling of the mercury and the pulp, confining the mixed pulp and mercury within a restricted space during such intermingling, causing the intermingled mass to travel in a substantially horizontal direction through a less restricted space, diluting the same with liquid, separating the heavier particles from the lighter by gravitation, and preventing the reintermingling of the settled particles.

16. The herein-described method of amalgamating metals, which consists in feeding a pulp by gravitation to a confined mercuryroaoee containing space, causing the passage of the pulp therethrough by the pressure of the incoming pulp alone, intermingling the pulp and mercury during the passage of the pulp, passing the mixture by the pressure of the incoming pulp through a less restricted space, opening up the materials thereof, separating the heavier particles therefrom, preventing further intermingling of the same, and causing the removal of the lighter sand and gangue by the pressure of the incoming pulp.

17. The herein-described method for amalgamating metals, Which consists in causing pulp to travel in a substantially horizontal direction through a mercury-containing confined space, intermingling the pulp and mer- PAUL A. KNAPPE.

Witnesses:

THOMAS E. BOOTH, EVERETT S. EMERY. 

